This invention relates to an assembling apparatus for a rotating electrical machine having permanently magnetized field magnets and more particularly to an improved mechanism for assembly such machines with a minimum of hand operation.
Many types of rotating electrical machines include a stator, which has affixed to its inner shell a plurality of circumferentially spaced permanent magnets. These permanent magnets cooperate with windings that are formed on a rotor that is juxtaposed to and rotates within the stator case. Obviously, the permanent magnets have a fairly large magnetic flux and this makes manual assembly of the stator case around the rotor difficult. The reason for this is that as the armatures of the rotor move into proximity with the permanent magnets of the stator case, they will be attracted and cause physical contact. This requires considerable strength of the assembler""s hands in order to prevent such contact or the permanent magnets and/or rotor could be damaged.
It has been the practiced to provide a rust proof surface treatment on the magnets; particularly in the use of neodymium-iron-boron magnets and any contact will cause this coating to be displaced. This can result in deterioration of the rust proofing quantities of the device.
It is, therefore, a principal object to this invention to provide an improved apparatus for assembling such rotation machines wherein the operator need not hold the components in spaced relationship when they are axially moved into registry with each other and so that the components will be held against engagement with each other during this assembling technique.
This invention is adapted to be embodied in an assembling apparatus for permanent magnet rotating electrical machines. The electrical machine includes a generally cylindrical stator case having permanent field magnets secured to an inside surface of the stator case and a rotor that is journalled by paired front and rear end closures attached to the stator case. The assembling apparatus comprises a jig for assembling and holding one end of the rotor and one of the end closures. A rotor holder smaller than the internal diameter of the stator is provided for holding the other end of the rotor in alignment with the rotational axis of the rotor. A stator case holder holds the stator case and is supported for movement along the rotor axis while holding the stator case. A driver is provided for assembling the stator case to the one end closure by relatively moving the stator case along the rotor axis while holding the other end of the rotor with the rotor holder.